The present invention relates to a lamp socket assembly, and more particularly to the arrangement of the metal contact in a lamp socket assembly.
A prior art lamp socket assembly with which this invention concerned is shown in FIG. 6 and includes a socket shell 2; a socket cap 3 fastened to the socket shell for holding down an electrical wire; a first metal contact A making electrical contact with the tip contact of a lamp bulb 4 and with one conductor of the electrical wire; and a second metal contact 24 making electrical contact with the ring contact of the lamp bulb 4 and with the other conductor of the electrical wire. The first metal contact A has a vertical front end A1, which is inserted through a hole 26 in the top wall of the socket shell 2 and which pierces the insulating covering of the electrical wire to make electrical contact with one conductor of the electrical wire. The first metal contact A also has a horizontal rear end disposed inside the socket shell below an inside projecting portion 25 on the top wall of the socket shell 2. When the base of the lamp bulb 4 is threaded into the socket shell 2, the tip contact and the ring contact of the lamp bulb make electrical contact with, respectively, the first metal contact A and the second metal contact 24. Normally, the horizontal rear end of the first metal contact A is spaced from the projecting portion 25 on the top wall of the socket shell 2; and, therefore, it makes electrical contact with the tip contact of the lamp bulb 4 when the lamp bulb is threaded into the socket shell 2.
Still referring to FIG. 6, when the lamp bulb 4 is threaded into the socket shell 2, the tip contact of the lamp bulb is spaced from the projecting portion 25 on the top wall of the socket shell 2 at a distance longer than the thickness of the horizontal rear end of the first metal contact A. However, the first metal contact A tends to undergo elastic fatigue after long use. Therefore, a poor electrical contact or no electrical contact may occur when the horizontal rear end of the first metal contact A is disposed constantly in contact with the projecting portion 25 of the top wall of the socket shell 2.